PIK3CA and gastric cancer: Mutations or deletions of the ARID1A gene have been detected in 8-25% of GC and are associated with concurrent gain-of-function mutations of PIK3CA and microsatellite instability.536,537 Another study by Zhang and colleagues revealed that ARID1A may function as a suppressor of GC cell proliferation by modulating PI3K/AKT pathway via targeting PIK3CA and PDK1. This provides a novel strategy of using PI3K and AKT inhibitors to treat GC with PI3K and AKT overexpression due to loss or deficiency of ARID1A. 538